Automatic casing filling apparatus



- July 16, 1957 E. H. CLARK; JR: 2,799,349

AUTOMATIC CASING FILLING APPARATUS Filed Aug. 12, 1955 4 (-II #0 35 I 42 as 9 3 37H Czazgle.

flrrolen zw AUTOMATIC CASING FILLING APPARATUS Earnest H. Clark, .lr., Downey, Calif., assiguor to Baker Oil Tools, Inc., Los Angeles, Calif., a corporation of California Application August 12, 1955, Serial No. 527,976 14 Claims. (Cl. 166-224) The present invention relates to the automatic filling of a tubular conduit string with fluid in a well bore as the string is being lowered in the well bore.

The apparatus disclosed in my application for Variable Orifice Casing Filling Apparatus, Serial No. 420,522, filed April 2, 1954, forms part of a conduit string, the fluid in a well bore flowing upwardly through an orifice portion of the apparatus as the tubular conduit string is lowered in the well bore, and around a valve element, continuing on upwardly into the conduit string. In many cases, the jetting action on the valve element of the fluid emanating from the orifice erodes the element so extensively as to render it incapable of later performing its valve function. The erosive wear is actually increased, and is caused to occur on other parts of the apparatus, by the fact that the action of the fluid passing upwardly from the orifice portion toward and around the valve element results in a downward sucking or downward movement of the valve element toward, and closer to, the orifice portion, which not only increases the force of the fluid jet on the valve element, but also creates an erosion of the orifice portion itself.

Accordingly, it is an object of the present invention to provide apparatus to form part of a tubular conduit string and embodying an orifice for controllably filling the conduit string as it is lowered through fluid in a 'well bore, in which the erosive action of fluid emanating from the orifice is considerably minimized.

Another object of the invention is to provide apparatus to form part of a tubular conduit string and embodying an orifice for controllably filling the conduit string as it is lowered through fluid in a well bore, and also a valve element above the orifice, in which the erosive action on the valve element of fluid issuing from the orifice is considerably minimized.

A further object of the invention is to provide an apparatus for automatically and controllably filling a conduit string in which the apparatus is embodied, in which erosive wear of the fluid flowing through the control orifice portion on the orifice portion itself is substantially reduced, if not completely eliminated.

Yet another object of the invention is to provide a deflector device in an orifice type of apparatus for controllably filling a string of well casing, and the like, which prevents the fluid jet emanating from the orifice from acting directly on a valve element above the orifice, thereby precluding fluid erosive action on the valve element.

Still a further object of the invention is to provide an orifice type of apparatus for controllably filling a conduit string as it is lowered through fluid in a Well bore, the apparatus including a valve element disposed initially above the orifice, but movable to a position therebelow, in which the fluid emanating from the orifice is prevented from eroding the valve element by a deflector device, which cannot preclude subsequent movement of the valve element to a position below the orifice.

States Patent This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a longitudinal section through an apparatus embodying the invention, with the parts occupying one relative position;

Fig. 2 is a view similar to Fig. l, disclosing a back pressure valve element shifted to prevent upward flow of fluid through the apparatus;

Fig. 3 is an enlarged bottom plan view of the deflector portion of the apparatus disclosed in Fig. 1;

Fig. 4 is an enlarged fragmentary longitudinal section through a portion of the orifice of the apparatus and the deflector thereabove.

The apparatus disclosed in the drawing has the purpose of controlling the rate at which fluid in a well bore can flow into a string of well casing, or similar tubular conduit string, as the latter is being lowered in the well bore to the desired depth. The apparatus is also efiective to prevent upward or return flow of fluid in the well casing after it has been filled with the well bore fluid, as for the purpose of preventing cementitious material from flowing back into the casing string following the completion of a cementing operation.

The specific apparatus A illustrated is a casing collar adapted to interconnect upper and lower casing sections B, C. The apparatus, however, may constitute the lower terminus of a string of well casing, in which event it is to be considered as a casing shoe.

The apparatus A consists of an outer tubular member 10 which may have an upper threaded box 11 threadedly secured to the lower pin end 12 of the upper casing section B, and a lower threaded pin 13 threadedly secured in the upper box end 14 of the lower casing section C. A valve mechanism is contained within the apparatus, and this valve mechanism is preferably made of readily drillable material. Thus, a portion of the interior of the tubular member may be filled by an annular plug 15 of cementitious material anchored to the tubular'member by external ribs 16 of the cementitious plug cast into longitudinally spaced internal grooves 17 in the tubular member-1t). This cementitious plug encompasses a valve body or housing 18 which may be made of several parts. An upper valve body 19 is held within the plug, this body having an inwardly projecting portion to provide a relatively wide transverse surface 20 hearing against the upper surface of a rubber or rubber-like orifice disc 21 having a comparatively small orifice. or passage 22 through its central portion.

The rubber disc 21 may be assembled to the lower end of the upper valve body 19 by causing a circumferential rib 23 on the latter to project downwardly into a companion upper groove 24 in the orifice disc. The orifice member 21 has a peripheral groove 25 to receive a rib 26 of cementitious plug material for the purpose of anchoring the orifice disc to the cement plug 15. Dependingv The rubber orifice disc 21 will control the passage of fluid in the string of well casing as the latter is lowered through the fluid in the well bore. It is also desired to cause the rubber orifice member to function as the seat of a back pressure valve, which is'preferably incorporated in the'apparatus. The upper end of the upper valve body 19 is inserted within a rubber deflector 31, which is, in turn, inserted within the lower end of an upper valve housing and retainer 32 encompassed by the upper portion of the cementitious plug 15. The rubber deflector 3.1 has an outwardly directed flange 33 engaging the lower end of the upper valve housing 32. This upper housing may contain a back pressure valve element 34, preferably in the form of a ball, buoyant in cement slurry. Upward movement of this ball 34 is limited by its engagement with a plurality of circumferentially spaced stop lugs 35 integral with and extending inwardly from the housing 32. It is to be'noted that the inside diameter of the housing 32. is substantially greater than the diameter of the ball 34, to allow fluid to flow around the ball valve element 34 and between the stop lugs 35 into the casing section B above the apparatus A.

A lower ball valve retainer housing 36 is disposed within the cementitious plug 15, the upper end of this housing being piloted within the lower portion of the lower valve body 28. This valve housing 36 is generally the same as the upper housing 32, but is inverted with respect thereto. It also has a plurality of circumferentially spaced stop lugs 37 engageable by the ball valve element 34, after the latter has been forced through the rubber orifice 21 in the manner described hereinbelow. The lower housing 36 also has an internal diameter substantially greater than the ball diameter, to allow fluid to flow therebetween when the ball is disposed in the lower housing 36.

The ball valve element 34 is initially positioned in the upper valve housing 32. The least diameter through the upper valve body 19, which is the diameter of the inner wall 30, is slightly greater than the diameter of the ball, to allow the ball 34, the deflector 31, and a ball stop member 38 hereinafter described, to be forced downwardly through the upper valve body 19 and against the rubber orifice disc 21. When suflicient pressure is imposed on the ball valve member 34, the latter bears against the deflector 31, forcing the latter against the stop member 38, the ball, deflector and stop member then being moved against the orifice disc 21, stretching its opening 22 sufliciently to force the ball stop member 38 v(which will probably be in broken form), the main portion of the rubber deflector 31, and the ball 34 completely therethrough and into the lower valve body 28 and lower housing 37. It is not desired that the ball 34 and deflector 31 move inadvertently through the orifice passage 22, which is the reason for providing the ball stop member 38 in the upper valve housing 19 above the rubber orifice disc 21 on which the ball and deflector will be stopped. This stop member or plate 38 serves to prevent downward movement of the ball 34 and deflector 31 through the orifice 21 until desired.

As disclosed in the drawings, the ball stop member or backing plate 38 extends inwardly from the upper valve body 19 to a substantial extent, being disposed between the orifice member 21 and the deflector 31. The backing plate 38 is normally arranged a slight distance above the rubber orifice disc 21, being integrated with the valve body 19 by a relatively small area 39 of shearable material. The backing plate has an on'fice 40 therethrough, which is substantially greater in area than the passage 22 through the orifice when the latter has no pressure differential thereacross. The area of the back-up plate passage 40 may be made equal to the maximum passage area that is desired through the apparatus, and will, therefore, place a limit upon the rate of flow of fluid into the well'casing as it is lowered in'the well bore. The backup plate 38 also serves as a stop or seat for the deflector 31 and the ball valve element 34, to initially prevent them from inadvertently being forced downward through the rubber orifice disc 21 into the lower body 28 and housin 36.

The deflector 31 is preferably made of rubber, or rubber-like material, and includes a central conical section 41 Whose apex 42 is disposed coaxial of the orifices 4t 22 through the back-up plate 38 and the rubber orifice disc 21. This central portion 41 is connected to the outer rim portion 43 of the rubber deflector member by a plurality of circumferentially spaced flexible ribs 44, which define openings 45 therebetween through which fluid can flow. The downwardly tapering conical dcflector section 41 will cause fluid passing upwardly through the rubber orifice disc 21 and the passage 40 in the back-up plate 38 to spread out or diverge, flowing through the deflector openings 45 and thence continuing on around the ball valve element 34 and into the upper casing section B thereabove. Thus, the deflector 31 will prevent any fluid passing through the rubber orifice 21 and the orifice 40 in the back-up plate 33 from acting directly upon the ball valve element 34, which would cause its erosion.

To prevent the fluid which is diverted outwardly by the conical deflector element 41 from eroding the flexible ribs 44 themselves, the deflector member is provided with generally triangular transverse tapered deflection portions 46 depending from the ribs 44. Each triangular portion has an upwardly and outwardly inclined lower edge 47 which is radial of a central plane passing through a rib 44, the upwardly divergent sides 48 of each triangular portion being inclined upwardly toward the openings 45 on each side of a rib. Thus, the opposed sides 48 of the triangular transverse deflector portions will guide the fluid issuing in an upward direction from the orifice 40 in the back-up plate 38 toward the openings 45 in the deflector member, very little of the fluid impinging upon the ribs 44 themselves. In other words, the fluid strikes the central conical deflector element 41 and then the opposed tapered sides 48 of the transverse deflector portions 46, being effectively separated into a plurality of streams directed toward the openings 45 between the flexible ribs 44 of the deflector member. From these openings 45, the fluid, which is actually being discharged in a lateral outward and upward direction, will pass around the ball valve element 34, with very little erosive eflect upon the latter, and continue on upwardly between the stop lugs 35 to the casing section B thereabove.

The diameter of the deflector member 31 where the ribs 44 join the rim portion 43 of the deflector member is slightly greater than the diameter of the ball valve member 34, the latter being slightly less than the diameter of the back-up plate 38 at its shearable region 39. When the ball 34 is to be transferred into the lower body 23 and housing 36, pressure applied to the fluid thereabove will force the ball 34 down against the deflector member 31, the latter stretching downwardly into contact with the back-up plate 38 until it substantially closes the orifice 40 through the latter, the back-up plate effectively closing the openings 45' through the deflector member itself. Pressure of a suflicient extent may now be imposed on the fluid above the ball 34, and when suificient in extent will shear the back-up plate 33 around its circumferential shearable portion 39, as well as shearing the deflector flexible ribs 44 from the rim portion 43 of the deflector. The back-up plate 38, deflector 31 and ball 34 are then forced through the rubber orifice disc 21. into the lower body 28 and housing 36, the ball 34 coming to rest upon the lower stop elements 37, whereas the back-up plate 38, which has probably been fractured into pieces as a result of its being sheared, and the rubber deflector 31 are pumped down through the housing 36 and into the casing section Ctherebelow. The stop lugs 37 prevent the ball 34 from being discharged from the lower housing 36.

With the apparatus disclosed, as the casing is being lowered in the well bore the fluid will pass upwardly through the orifice passage 22, continuing on up through the back-up plate orifice 40, being deflected in an up ward and laterally outward direction toward the openings 45 in the deflector plate 31 toward the wall of the upper housing 32, the fluid flowing around the ball 34 and between the upper stop lugs 35 into the casing section B thereabove. In the absence of the deflector member 31, the fluid would leave the orifice 40 in the back-up plate 38 and would discharge directly as a high velocity jet of fluid against the ball valve member 34, creating ero- 'sive wear on the latter, oftentimes to the point where it 'would be useless. As a matter of fact, the striking of such a concentrated and central jet of fluid against the ball 34 causes the fluid to be deflected laterally around the latter, the velocity of the fluid creating a lower pressure below the ball than above it, with the result that the ball 34 is actually sucked in a downward direction substantially close to the back-up plate 38, tending to restrict the flow of fluid through the back-up plate, since the ball throttles the opening 40 through the latter. As a result, the jet of fluid striking the ball actually originates at the orifice 22 through the rubber disc 21, this fluid then moving at very high velocity through the restricted annular opening between the ball 34 and the back-up plate 38. Such high velocity movement of fluid not only erodes the ball 34, but it also erodes the backup plate as well.

By virtue of the incorporation of the deflector 31 described above, the ball 34 remains in its upper position against the stop lugs 35 during lowering of the casing string through the fluid in the well bore, the deflector 31 directing the fluid issuing from the back-up plate 38 laterally outward directly through the deflector openings 45 and harmlessly around the ball.

During lowering of the well casing through the fluid in the well bore, as the pressure differential across the rubber disc 21 increases, it is bulged in an upward direction, increasing the area of the orifice 22. However, as the pressure differential increases, the rubber disc 21 is eventually bulged upwardlyinto contact with the back-up plate 38, which will prevent its further upward bulging and further increase in the area of the orifice passage 22. When the rubber disc 21 engages the back-up plate 38, the area of the passage 21 is preferably less than the area of the passage 40 through the back-up plate. If the pressure diiferential were to increase to still a further extent, the rubber material around the orifice passage 22 would actually be forced partly into back-up plate passage 40. Such deformation of the rubber material will cause the'rubber orifice passage 22 to decrease in size, thereby retarding the rate of fluid flow through the orifice 22 into the casing string B thereabove.

With the fluid flowing relatively upwardly in the casi'n'g string in the manner described, the deflector member 31 itself is also bulged in an upward direction, but this upward bulging will have no eifec't on the performance 'of its deflecting function to prevent erosive wear on the ball member 34.

After the casing string has been lowered to the desired depth and the casing has been allowed to fill completely with fluid in the well bore, the fluid in the well easing can be subjected to sufficient pressure from above to force the ball 34 downwardly, the ball engaging the deflector 31 and bulging or stretching it in a downward direction until the deflector is in engagement with the upper seat 38a of the back-up plate 38, the latter effectively closing the passages 45 through the deflector itself. Pressure can now be built up to a sufficient extent (for example, to 1,000 )9. s. i.) to shear the backup plate 38 at its region 39 from the upper valve body 6 19 and to shear the outer portions of the flexible ribs 44 from the rim portion 43 of the disc 31. Not only is the back-up plate 38 sheared, but since it can be made of cast iron, or similar readily breakable material, it will actually shatter or break into many pieces, such pieces, together with the main portion of the deflector member 31, being completely through the orifice disc 21 ahead of the ball 34, the latter, of course, also passing through the orifice 22 and into the lower valve body 28 and housing 26, where it can later function as a back pressure valve element, moving upwardly into engagement with the rubber orifice disc 21 as a companion valve seat. The shattered pieces of the back-up plate 38 and the deflector 31 will be pumped completely out of the apparatus A. When pumped through the disc 21, and upon the relieving of the pressure in the casing string above the apparatus, the disc 21 will inherently resume its original shape, such as disclosed in Fig. 2.

Fluid can now be pumped downwardly through the casing string, this fluid passing through the upper housing 32 and upper valve body 19 and through the rubber orifice passage 22, flowing into the lower valve body 28 and lower housing 36, from where it passes around the ball 34 and between the lower stop lugs 37, and out into the lower casing section C for discharge into the well bore. If the well casing is to be cemented in the well bore, the required quantity of cement slurry can be pumped down the casing string, this cement slurry being pumped through the orifice 22. If the pressure above the orifice member 21 increases, then the latter will merely bulge in a downward direction to increase the orifice area, allowing a greater rate of flow of the cement slurry through'the apparatus. The cement slurry will discharge from the casing at some point below the apparatus A and will then pass upwardly into and through the annulus between the exterior of the casing string and the wall of the well bore. When suflicient cement slurry has been deposited behind the casing string, the pressure inside of the well casing may be relieved. The cement slurry will'tend to flow back into the casing string, but in so doing it will elevate the ball valve member 34 into engagement with the rubber orifice disc 21. When the ball valve element engages the disc, it eflectively closes the orifice 22 against upward passage of fluid therethrough. If the back pressure is high, it will merely force the ball upwardly to bulge the orifice disc 21 in an upward direc tion. However, the upper valve body 19 projects inwardly to a substantial extent, the minimum diameter of this upper valve body being only slightly greater than the diameter of the ball 34. As a result, the ball 34 will expand the rubber material between it and the upper valve body 19 with great force, the rubber material and ball preventing upward passage of fluid back through the upper valve body 19, even under high back pressure differential conditions. I

After the cement slurry has set and hardened, the internal mechanism of the apparatus can be disintegrated by a suitable drill bit. Substantially all of the internal mechanism is made of readily drillable material. The cementitious plug 15 is readily drillable, as well as the upper and lower housings 32, 36, the upper and lower valve bodies 19, 28, the rubber disc 21, and the outer portion of the rubber deflector plate 31 remaining in the apparatus after its inner portion has been sheared therefrom. The housing 32, 36 and body 28 may be made of a suitable synthetic resin, whereas the valve body 19 can be made of cast iron, the ball 34 itself also being made of a suitable synthetic resin. The internal mechanism is readily removable under the action of the drill bit, and since it is relatively short in length, the time required to effect its disintegration by a drill bit is reduced.

The inventor claims:

1. 'In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; an orifice member secured in said tubular member and extending across said passage, said orifice member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; and a deflector member in said tubular member above and adjacent said orifice member in position to laterally deflect fluid flowing upwardly through said orifice in a divergent stream, said deflector member having an opening through which said divergent stream of fluid can flow.

2. In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and extending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said orifice member at a restricted rate; and a deflector member within and detachably secured to said tubular member and disposed above and adjacent said elastic member in position to laterally deflect fluid flowing upwardly through said orifice, said deflector member having an opening through which fluid from said orifice can flow, said deflector member being detachable from said tubular member in response to fluid pressure above said deflector member to be forced through said orifice to a position below said elastic member.

3. In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; an orifice member secured in said tubular member and extending across said passage, said orifice member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a deflector member movable in said tubular member and disposed above and adjacent said orifice member in position to laterally deflect fluid flowing upwardly through said orifice, said deflector member having an opening through which fluid from said orifice can flow; and means on said deflector member engageable with said orifice member, upon downward movement of said deflector member in said tubular member, to substantially close said orifice.

4. In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and extending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said orifice member at a restricted rate; a deflector member within and detachably secured to said tubular member and disposed above and adjacent said elastic member in position to laterally deflect fluid flowing upwardly through said orifice, said deflector member having an opening through which fluid from said orifice can flow, said deflector member being detachable from said tubular member in response to fluid pressure above said deflector member to be forced through said orifice to a position below said elastic member; and means on said deflector member engageable with said elastic member, upon downward movement of said deflector member in said tubular member, to substantially close said orifice.

In apparatus as defined in claim 2; wherein said deflector member is pliant and elastic.

6. In apparatus as defined in claim 4; wherein said deflector member is pliant and elastic.

7. In apparatus of the character described: a tubular member having a passage and adapted to form part of .a tubular conduit string to be lowered in a well bore; an orifice member secured in said tubular member and extending across said passage, said orifice member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; and a deflec- 8 r tor member in and extending across said tubular member above and adjacent said orifice member, said deflector member having a central depending tapered portion in alignment with said orifice against which fluid from said orifice will strike and be deflected laterally in a divergent stream, said deflector member having an opening through which such deflected divergent stream of fluid can pass.

8. In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; an orifice member secured in said tubular member and extending across said passage, said orifice member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a valve member in said tubular member above said orifice member; and a deflector member in said tubular member between said orifice member and valve member and disposed adjacent said orifice member to laterally deflect fluid flowing upward through said orifice in a divergent stream, said deflector member having an opening through which said divergent stream of fluid can flow.

9. In apparatus of the character described: a tubular member having a passage and adapted to form part of a conduit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and extending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a valve member substantially larger in cross-sectional area than said orifice movable longitudinally within said tubular member from above said elastic member, through said orifice, to the opposite side of said elastic member; and a movable deflector member detachably secured to said tubular member and disposed between said elastic member and valve member when said valve member is above said elastic member in position to laterally deflect fluid flowing upwardly through said orifice, said deflector member having an opening through which fluid from said orifice can flow, said deflector member being detached from said tubular member to move with said valve member through said orifice to a position below said elastic member.

10. In apparatus as defined in claim 9; wherein said deflector member is pliant and elastic. 1

11. In apparatus of the character described: a tubular member having a passage and adapted to form part of a tubular conduit string to be lowered in a well bore; an orifice member secured in said tubular member and extending across said passage, said orifice member having anorifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a valve member in said tubular member above said orifice member; and a deflector member in said tubular member between said orifice member and valve member, said deflector member having a central tapered portion in alignment with said orifice against which fluid from said orifice will strike and be deflected laterally in a divergent stream, said deflector member having an opening through which said deflected divergent stream of fluid can pass.

12. In apparatus of the character described: a tubular member having a passage and adapted to form partflof a conduit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and ex tending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a stop member above said elastic member detachably secured to said tubular member; a movable valve member substantially larger in cross-sectional area than said orifice disposed above said stop member; a movable deflector member in said tubular member between said stop member and valve member to deflect fluid moving upwardly through said orifice laterally, said deflector member having an opening through which fluid from said orifice can flow; said valve member being movable downwardly into engagement with said deflector member to move said deflector member downwardly into engagement With said stop member to detach said stop member from said tubular member and enable said valve member and deflector member to move down through said orifice to a position below said elastic member.

13. In apparatus of the character described: a tubular member having a passage adapted to form part of a conduit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and extending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a backing member detachably secured to said tubular member above and adjacent said elastic member, said backing member having a passage therethrough of greater area than said orifice, said elastic member being deformable by fluid in the well bore to increase the area of its orifice to an extent limited by engagement of said elastic member with said backing member; a valve member above said backing member; a movable deflector between said valve member and backing member to deflect fluid moving upwardly through said orifice and backing member laterally, said deflector member having an opening through which fluid from said orifice and backing member passage can flow; said valve member being movable downwardly into engagement with said deflector member to move said deflector member downwardly into engagement with said backing member to detach said backing member from said tubular member and enable said valve member, deflector member and backing member to move down through said orifice to a position below said elastic member.

14. In apparatus of the character described: a tubular member having a passage adapted to form part of a condnit string to be lowered in a well bore; a pliant, elastic member secured in said tubular member and extending across said passage, said elastic member having an orifice therethrough to allow fluid to flow through said tubular member at a restricted rate; a backing member detachably secured to said tubular member above and adjacent said elastic member, said backing member having a passage therethrough of greater area than said orifice, said elastic member being deformable by fluid in the well bore to increase the area of its orifice to an extent limited by engagement of said elastic member with said backing member; a valve member above said backing member; a movable deflector member in and extending across said tubular member between said valve member and backing member, said deflector member having a central depending tapered portion in alignment with said backing member passage against which fluid from said orifice will strike and be deflected laterally, said deflector member having an opening through which such deflected fluid can pass; said valve member being movable downwardly into engagement with said deflector member to seat said deflector member against said backing member to substantially close the passage therethrough and enable fluid pressure above said backing member to detach said backing member from said tubular member and then allow said backing member, deflector member and valve member to move through said orifice to the opposite side of said elastic member.

References Cited in the file of this patent UNITED STATES PATENTS 2,737,195 Baker et a1. Mar. 9, 1956 

